Manufacture of metallic sodium



' and WILLIAM R.

ALBERT w. smrrn AND WILLIAM R. VEAZEY, OF CLEVELAND, OHIO.

MANUFACTURE OF METALLIC SODIUM.

saasao;

No Drawing.

To all whom it may concern:

Be it known that we, ALBERT W. SMITH VEAZEY, citizens ofthe United States, and residents of Cleveland, county of Cuyaho'ga, State of Ohio, have jointly invented a new and useful Improvement in the Manufacture of Metallic Sodium, of which the following is a specification, the principle of the invention being herein explained and the best mode in which we have contemplated applying that principle, so as .to distinguish it from other inventions. g

The present invention relates more particularly to the electrolytic manufacture of metallic sodium, which, as is Well known, is

at present extensively carried on, using caustic soda (N aOH) as the materialto be electrolyzed. Despite the extensive commercial use made of this so-called Castner process, a number of difliculties attend the electrolysis of caustic soda. Thus for example only'one-half of the electric current "used is employed in giving sodium, the other half producing hydrogen by the electrol sis of the hydroxyl resulting from the rst step. The hydrogen and oxygen that are produced from an explosive mixture, w1th the result that the cells when in operation are continuall subject to more or less dangerous expl to scatter fine particles of caustic in the atmosphere, if, no more serious damage results. Furthermore, the metallic sodium is soluble in fused sodium hydroxid, except for a relativelylimited temperature range, and this adds to the-diflicu'lty of the operation by making it necessary to prevent any wide fluctuation of the temperature within the cell;

By reason of the aforementioned difliculties, and for the further reason that some cheaper material than, caustic would vof course be desirable, a number of other compounds of sodium have heretofore been trled, but none successfully. so far as we are advised. Commonsalt (NaCl), which would probably afford; the cheapest source, unfortunately has so high a melting polntthat the sodium volatilizes and burns as 1t is formed, and the same is true of all the other available compounds or salts of sodium when used alone. It has also been attempted to work with mixtures of different salts. For example, caustic soda has been added to sodium carbonate (Na CO which latter Specification of Letters Patent.

Application filed July 16,

' endeavor to obtain ends, the invention,

osions which at least serve,

"Pa-tented Apr. 19,1921.

1917. Serial No. 180,742.

alone fuses at too high a temperature, in an a lower fusing mixture; the result, however, is unsatisfactory because the caustic soda electrolyzes preferentially, and no advantage is accordingly gained.

The object of the present invention is to provide a suitable mixture of sodium compounds or salts for use in this electrolytic process, whereby metallic sodium may be produced at a much lower cost, not only by reason of the cheapening of the source-material, but also by requiring less current and otherwise simplifying and rendering less dangerous the operation itself. To the accomplishment of the foregoing and related then, consists of the steps hereinafter fully described and particularly pointed out in the claims.

The following description sets forth in detailone approved mode of invention, such disclosed mode, however, constituting but one of the various ways in whiich the principle of the invention maybe use We have discovered that sodium compounds, and specifically sodium carbonate, upon being added to sodium salts other than caustic soda, in proper proportions,- will give a mixture capable of fusion at a low enough temperature to avoid the vaporization and burning of the metallic sodium. At the same time, by a proper selection of these other sodium compounds, the carbonate or selected compound will electrolyze preferentially, which means that it is dissociated into its constituent elements at a lower voltage than the admixed compounds.

The following examples illustrate mixtures of the sort generally referred to above, which have been found satisfactory in actual practice 44 parts of sodium chlorid (NaGl') were mixed with 56 parts of potassium chlorid (K01). This gives a mixture which fuses at approximately 640 C.,-and from such fused mass the sodium maybe electrolyzed out Without serious danger of ignition, although a lower temperature would be desirable.-

As an example of a mixture having a lower point of fusion than the one just described, 347 parts of sodium chlorid were added to 65.3 parts of sodium carbonate. The resultant mixture has a melting point of approximately 620 0., and fromsuch carrying out the I of sodium chlorid, 43.5 parts of sodium carbonate, and 33.3 parts of potassium chlorid, was made, such mixturehaving a. melting point of approximately 565 (J. From this mixture, "as in the case of the second one, the sodium carbonate will be electrolyzed in preference to the other compounds present, the latter remaining as a bath or diluent for the carbonate. Of course to keep the melting point of the mixture down, it is necessary to add more of the carbonate, or other salt being electrolyzed, as the electrolysis proceeds.

Any suitable electrolytic cell may be employed in connection with the foregoing, a regular Castner caustic soda cell having been found entirely satisfactory in actual practice. With the sodium carbonate mixtures described above, it has been found possible to work with a potential of four Volts between the.terminals of the electric machine, indicating that only a few volts are re uired to effect the dissociation. A

ther modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the method herein disclosed, provided the step or steps stated by any one of the following claims or the equivalent of such stated steps or steps be employed.

We therefore particularly point out and distinctly claim as our invention:

1. The method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and another salt, the ingredients being proportioned so that such mixture has a lower melting point than any of its constituents.

2. The method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and a halogen salt of sodium the ingredients being proportioned so that such mixture has a lower melting point than any of its constituents.

3 The method of making metallic sodium, whlchconsists in electrolyzing sodium carbonate 111 a fused mixture of such salt and sodium chlorid the ingredients being proportioned so that such mixture has a lower meltin point than any of its constituents.

4. T e method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and sodium and potassium chlorids the ingredients being proportioned so that such mixture has a lower melting point than any of its constituents.

5. The method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and halogen salts of potassium and sodium the ingredients being proportioned so that such mixture has a lower melting point than any of its constituents.

6. The method of making metallic sodium,

which consists in electrolyzing sodium carbonate in a fused mixture of such salt and sodium and potassium chlorids in such proportion as to give such mixture a melting point of less than 600 C.

7. The method of making metallic sodium,

which consists in electrolyzing sodium carbonate in a fused mixture of such salt and sodium and potassium chlorids, the amount of such carbonate by weight being less than' bonate in a fused mixture of such salt and sodium and potassium chlorids in the proportion of 43.5 to 23.2 to 33.3 parts by weight, respectively;

Signed by us, this 14th day of July, 1917.

ALBERT W. SMITH. WILLIAM R. VEAZEYN' 

